I see the search module is based on Lucene.net, but the query parser syntax is different with Lucene.net.

for example, i have two content:

title: cat dog bird
body: table bed light window

title: cat
body: table

If I search "cat + bird", the result is different with "cat AND bird". AND operator only returns one content, but + operator returns all the two contents.
If I search "title:cat", there is nothing returned. but in lucene.net, the result is the contents which has "cat" in the title.